Secondary Battery Electrolyte Composition for Low-Resistance SEI Stability
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Solution Overview
Problem
Lithium secondary batteries face challenges in improving output characteristics, high-temperature storage stability, and reducing gas generation and thickness increase rates due to poor electrolyte additives, which affect discharge resistance and cycle life.
Innovation Solution
An electrolyte composition including an organic solvent, lithium salt, a first additive with a specific structure, and a second additive with a symmetric atomic group, which reduces discharge resistance and enhances high-temperature recovery capacity by forming a stable film on electrodes, suppressing gas generation and thickness increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte additives are used, then basic battery function is maintained, but output characteristics and high temperature storage characteristics deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a fluorinated cyclic carbonate compound with specific molecular structure (Formula 1) and controlling its content within 5-50 wt% of total electrolyte. This parameter change enables the formation of a stable SEI film that maintains both output characteristics and high temperature storage stability, resolving the contradiction between power and reliability.
Solution Approach 2:
The patent creates a composite electrolyte system by combining the fluorinated cyclic carbonate compound (Formula 1) with conventional additives like vinylene carbonate and fluoroethylene carbonate. This composite approach synergistically improves both output characteristics and high temperature storage characteristics, achieving neither property alone with single additives.
2Stability of the object's composition
If electrolyte additives are increased to improve film characteristics, then SEI film formation improves, but gas generation and thickness increase rate worsen
Solution Approach 1:
The patent optimizes the concentration parameter of the fluorinated cyclic carbonate compound to 5-50 wt% of total electrolyte. This specific parameter range enables effective SEI film formation while suppressing excessive gas generation and thickness increase, resolving the contradiction between film stability and harmful byproducts.
Solution Approach 2:
The patent converts the potential harmful effect of electrolyte decomposition into a beneficial outcome by using the fluorinated cyclic carbonate compound to form a stable SEI film that prevents further decomposition. The initial decomposition products form a protective layer that actually reduces subsequent gas generation and swelling, turning harm into benefit.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The electrolyte composition improves battery output, extends lifespan, and maintains high-temperature storage capacity by reducing discharge resistance and gas generation, while stabilizing the electrode structure, thus enhancing overall battery performance and safety.
Implementation Method 1
electricity is generated or consumed through oxidation-reduction reactions due to intercalation and de-intercalation at the positive and negative electrodes
Implementation Method 2
various studies are being conducted on organic solvents and additives as electrolyte components to improve battery characteristics such as output characteristics, cycle characteristics, preservation characteristics, and film characteristics
Implementation Method 3
an electrolyte additive capable of improving output characteristics and high temperature storage characteristics of the battery and significantly reducing gas generation and thickness increase rate
Data Source
AI summary
Disclosed is an electrolyte and a secondary battery containing the same. According to the present disclosure, charging efficiency and output may be improved due to low discharge resistance, and gas generation and thickness increase may be suppressed to provide a secondary battery with long-term lifespan and excellent high temperature capacity retention.